1,Purpose: steel structure fastening, etc 2,Quality assurance preferential price 3,Prompt delivery, and transportation safet 1, ... ,ISO 15480, ISO 15481, ISO 15482, ISO 15483,Hex Washer Head Self Drilling and Tapping Roofing Screws;DIN7504K,SAE J78,ISO 15480, ISO ... ,Nylon Head Self Drilling and Tapping Roofing Screws;DIN7504K,SAE J78,ISO 15480, ISO 15481, ISO 15482, ISO 15483,Concrete Screw;DIN7504K,SAE ...